The present invention relates to a method and an apparatus for detecting a consuming state of ink within an ink tank, and an ink jet recording apparatus and an ink tank to which the method of detecting and the apparatus for detecting are applied.
In general, an ink jet recording apparatus is configured so that the ink jet recording apparatus includes a carriage on which an ink jet type recording head equipped with pressure generation means for applying a pressure to a pressure generation is chamber and a nozzle opening from which an pressurized ink is discharged as an ink droplet is mounted, and an ink tank for containing the ink supplied to a recording head via a pass and continuously printable. In general, an ink tank is configured as a cartridge attachable to and detachable from the recording apparatus so that at the time when the ink is completely consumed, the ink tank is easily changeable by the user.
Conventionally, as a method of managing an ink consumption of an ink cartridge, a method of mathematically managing an ink consumption by adding up a count number of ink droplets discharged by a recording head, and a volume of ink absorbed in the maintenance step of a printing head using a software, a method of managing an ink consumption by detecting a point in time at which the predetermined volume is actually consumed by mounting two pieces of electrodes for directly detecting an ink level on an ink cartridge and the like have been known.
However, as for a method of mathematically managing an ink consumption by adding up the count of discharging ink droplets and a volume of the ink absorbed using a software, there has been a problem that the pressure within an ink cartridge and viscosity of the ink are changed by the circumstances used, for example, a high or low temperature and humidity within a room used for it, a lapsed time after opening a sealed ink cartridge, the difference of using frequency of the user side and the like, and the error not to be negligible is generated between an ink consuming volume mathematically added up and an actual volume of consumption. Moreover, in the case where the same cartridge is removed once and mounted again, there has been also a problem that an added up counting value is once reset, therefore, an actual ink residual volume becomes completely unknown.
On the other hand, as for a method of managing a point in time at which the ink is consumed using electrodes, since an actual volume of the ink at some point in time can be detected, an ink residual volume can be managed with a high degree of reliability. However, the ink must be electrically conductive for detecting an ink level, hence, kinds of inks for use are limited. Moreover, there is a problem that fluid-tight structure between electrodes and an ink cartridge becomes complex. Furthermore, since usually noble metal having a good conductivity and corrosion resistance is used as a material for an electrode, there has been also a problem that a manufacturing cost of an ink cartridge is increased. Moreover, since two pieces of electrodes are required to be mounted at different positions, respectively, there has been a problem that the number of steps for manufacturing it is increased, and as a result, the manufacturing cost is increased.
The present invention is achieved in consideration of the above-described circumstances, and an object of the present invention is to provide a method and an apparatus for detecting an ink consumption capable of precisely detecting a liquid consuming state.
The present invention provides a technology for detecting a liquid residual volume by especially utilizing an oscillation, and particularly is capable of precisely and finely detecting a change of a liquid volume.
Moreover, an object of the present invention is to provide a liquid container which is capable of precisely detecting a consuming state of a liquid and does not require a complex sealing structure.
Moreover, another object of the present invention is to provide an ink cartridge capable of precisely detecting a consuming state of the ink and not requiring a complex sealing structure.
It should be noted that the present invention is not limited to an ink cartridge, and the other liquid containers are also applicable.
An aspect of the present invention is a method of detecting an ink consuming state of an ink tank used for an ink jet recording apparatus. The method employs an estimate consumption calculation processing in combination with an actual consumption detection processing. In the estimate consumption calculation processing, an estimate consuming state of the ink within an ink tank is required. Ink consumption is an ink consumption by printing (can be found based on an amount of printing), an ink consumption for maintenance of an ink head and the like. Actual volume of consumption detection processing is to detect an actual volume of consuming state by detecting an oscillating state corresponding to an ink consuming state using a piezoelectric device.
According to the present invention, an actual consuming state can be detected by employing a piezoelectric device. On the other hand, according to an estimate processing, although accompanying with somewhat errors, a consuming state can be found in detail. Therefore, an ink consuming state can be precisely found in detail by the combined use of both processings.
Preferably, the actual consumption detection processing detects an ink liquid level passing through the piezoelectric device as the actual consuming state. When an ink liquid level passes through the piezoelectric device, an output of the piezoelectric device is largely changed. Therefore, the ink liquid level is securely detected. At least one of ink consuming states prior to and after the passage of the liquid level portion is found in detail by the estimate consumption calculation processing. For example, making the passage of the ink liquid level as a starting point, subsequent volume of consumption is calculated. An ink consuming state is found precisely and in detail by performing these processings.
Preferably, when detected that an ink liquid level passes through the piezoelectric device, the detection of the actual consuming state is completed. Owing to this, an operation of the piezoelectric device is limited when it is necessary to be done so. Specifically, useless operations of the piezoelectric device and actual consumption detection processings accompanying with them are omitted.
In the estimate consumption calculation processing, the estimate consuming state may be found by adding up the number of ink droplets ejected from a recording head. Furthermore, in the estimate consumption calculation processing, the estimate consuming state may be found on the basis of a size of an ink droplet ejected from the recording head.
Preferably, in the estimate consumption calculation processing, consumption conversion information indicating the relationship between an amount of operation of an ink jet recording apparatus and a volume of ink consumption is corrected on the basis of the detection results of the actual consumption detection processing, and the estimate consuming state is found on the basis of the corrected consumption conversion information. The consumption conversion information may be information of a volume of ink consumed during the time of maintenance. The foregoing consumption conversion information may be also a volume of the ink corresponding to the ink droplet ejected from the recording head. A conversion parameter which indicates the relationship between the printing amount and the consuming state is different little by little due to ink jet recording apparatus and ink tanks and further combinations thereof. The error due to such differences of parameters can be reduced, therefore, a consuming state is more precisely found.
The corrected consumption conversion information may be also used to be limited to the ink tank which is an objective of the correction. Otherwise, the corrected consumption conversion information is not limited to the ink tank which is an objective of the correction, may be also used for an ink tank mounted later. The latter is, for example, advantageous in the case where the influence due to individual differences of ink jet heads on the consumption conversion parameter is large. Each ink jet recording apparatus can utilize consumption conversion information applicable to its head.
Preferably, in the estimate consumption calculation processing, the estimate consuming state is corrected on the basis of the detection results of the actual consumption detection processing. The foregoing estimate consumption calculation processing may be a processing for finding the estimate consuming state by adding up the number of ink droplets ejected from a recording head. When the detection results of the actual consumption detection processing are obtained, the estimate consuming state found by adding up until then is corrected. According to this form, when the actual consuming state is detected, the error generated during the estimate consumption calculation processing until then is corrected. Therefore, an ink consuming state can be precisely found.
In the present invention, the consuming state information is, for example, used as follows: a possibly available printing amount using the remaining ink may be indicated on the basis of the obtained consuming state which has been found. The remaining ink volume may be indicated on the basis of the consuming state which has been found. When the remaining ink volume is indicated, different colors may be employed corresponding to the ink volume. When the remaining ink is indicated, different graphic forms corresponding to volume of ink may be employed. An ink jet recording apparatus may be controlled in a different form on the basis of the consuming state information. For example, when the ink container is empty, the printing processing is stopped.
Moreover, in the present invention, the necessity and timing of the ink refilling or an ink tank exchange may be determined on the basis of the estimate consuming state. The necessity and timing of the ink refilling or an ink tank exchange may be determined on the basis of the actual consuming state.
The foregoing piezoelectric device employed in the actual consumption detection processing may be provided nearby the ink supplying opening of the ink tank.
The interior of the ink tank may be separated by at least one of partition walls into a plurality of chambers which are communicated with each other. The piezoelectric device employed in the actual consumption detection processing may be set on the upper portion of the chamber in which the ink is consumed later. It may be set so that a volume of a chamber where the ink is used later is smaller than a volume of a chamber where the ink is used ahead.
Preferably, the consuming state is stored in storage means, for example, the consuming state memory. The foregoing memory device may be a memory device mounted on the ink tank. This form is advantageous with respect to the removal of an ink tank. An ink tank is removed, and when it is mounted again, the consuming state is easily found.
The above-described consumption conversion information may be stored in the consuming state memory. The consumption conversion information following the correction on the basis of the actual consuming state may be stored. These information are also read from the memory when the ink tank is mounted, and preferably utilized.
The foregoing actual consumption detection processing section detects an actual consuming state on the basis of change of acoustic impedance accompanying with a liquid consumption using the piezoelectric device. The piezoelectric device may output a signal indicating a residual oscillating state after an oscillation is generated. The foregoing actual consuming state is detected on the basis of the remaining oscillating state being changed corresponding to the ink consuming state.
Moreover, the piezoelectric device may generate an elastic wave toward the interior of the liquid container and generate a detection signal corresponding to the reflected wave with respect to the elastic wave.
When the actual consuming state is detected by the actual consumption detection processing, the remaining possibly available printing amount may be calculated on the basis of the actual consuming state. When the possibly available printing amount is printed, the printing data prior to the printing may be stored in a printing data storage section.
Another aspect of the present invention is an ink jet recording apparatus having a consumption information memory for storing information concerning with an ink consuming state of an ink tank. The consumption information memory is composed of a semiconductor memory. In the consumption information memory, an estimate consuming state of the ink within the ink tank, an actual consuming state obtained by detection of an oscillating state corresponding to an ink consuming state using a piezoelectric device and ink end event information obtained as the actual consuming state, the ink end event information for indicating the generation of an ink end event, and an ink liquid level passing through the piezoelectric device are stored. Preferably, when the ink tank is mounted, the ink end event information stored in the consumption information memory is read. The ink jet recording apparatus determines whether or not an ink liquid level passes through the piezoelectric device, and in the case where it has already passed through, the predetermined operations are performed.
According to this aspect, an estimate consuming state, an actual consuming state and ink end event information are stored in the semiconductor memory. Those information are appropriately read and used. Preferably, ink end event information is stored in a storage region separate from the other consuming state information. When only seeing the ink end event information, it is easily found whether or not an ink liquid level has already passed through the piezoelectric device. This information is, for example, available in an ink tank mounting operation. Whether or not the ink exists in the mounted ink tank is informed to the user. In this way, by employing the ink end event information, the ink jet recording apparatus can be appropriately operated corresponding to the ink consuming states.
Another aspect of the present invention is an ink tank mounted in an ink jet recording apparatus, and has a consumption information memory for storing information concerning with an ink consuming state. The consumption information memory may be composed of a semiconductor memory. In the consumption information memory, an estimate consuming state of the ink tank and ink end event information obtained as an actual consuming state using a piezoelectric device, which indicates the generation of an ink end event in which an ink liquid level passes through the piezoelectric device are stored. According to this aspect, an effect similar to that of the aspect of an ink jet recording apparatus of the above-described ink end event is also obtained.
Another aspect of the present invention is an apparatus for detecting an ink consuming state of an ink tank used for an ink jet recording apparatus. This ink consumption detection apparatus includes an estimate consumption calculation processing section for finding an estimate consuming state by calculating an ink consuming state of the ink tank on the basis of the consumption conversion information, an actual consumption detection processing section for detecting an actual consuming state using the piezoelectric device mounted on the ink tank, a conversion information correction processing section for correcting the consumption conversion information on the basis of the actual consuming state, and a consumption information storage section for storing and providing a corrected consumption conversion information prior to and after the correction of the reference consumption conversion information to the estimate consumption calculation processing section.
Preferably, the consumption information storage section is provided on the ink tank. The consumption information storage section stores the corrected consumption conversion information along with the correction objective identification information for identifying an ink jet recording apparatus on which the ink tank has been mounted when the consumption conversion information was corrected. The foregoing estimate consumption calculation processing section uses its corrected consumption conversion information when the corrected consumption conversion information obtained making the ink jet recording apparatus as an objective is stored in the consumption information storage section. The estimate consumption calculation processing section uses the reference consumption conversion information when the corrected consumption conversion information obtained by making the ink jet recording apparatus as an objective is not stored in the consumption information storage section. Preferably, the estimate consumption calculation processing section selects the reference consumption conversion information or the corrected consumption conversion information based on the corrected objective identification information when the ink tank is exchanged.
According to the present invention, the corrected consumption conversion information is used only in the ink jet recording apparatus when its correction is performed by making reference to the corrected objective identification information. A situation that the corrected consumption conversion information is used in another ink jet recording apparatus can be avoided. For example, when an ink tank is removed from the recording apparatus and mounted on another recording apparatus, reference consumption conversion information is used. When the ink tank is mounted on the same recording apparatus again, the previous corrected consumption conversion information is used. In this way, since appropriate consumption conversion information is used, an ink consuming state is precisely found.
The foregoing corrected objective identification information may be information for identifying a kind of the ink jet recording apparatus. The foregoing corrected objective identification information may be information for individually identifying an ink consumption related constitution of the ink jet recording apparatus. The foregoing corrected objective identification information may be information for identifying a recording head of the ink jet recording apparatus.
Preferably, the ink tank has a plurality of piezoelectric device in different locations. The foregoing actual consumption detection processing section detects that an ink liquid level passes through each piezoelectric device. The foregoing conversion information correction processing section finds the corrected consumption conversion information on the basis of an estimate consuming volume (printing amount and/or the number of frequency of maintenance may be used) obtained from the point in time when one piezoelectric device detects the passage of a liquid level portion to the point in time when the next piezoelectric device detects the passage of a liquid level portion. The foregoing estimate consumption calculation processing section finds the consuming state by switching from the fundamental consumption conversion information to the corrected consumption conversion information when the corrected consumption conversion information was obtained. Preferably, after the ink tank was exchanged, when a plurality of piezoelectric devices have detected ink liquid level, the corrected consumption conversion information is found, and switched from the fundamental consumption conversion information to the corrected consumption conversion information.
According to this form, when the ink tank is mounted on the ink jet recording apparatus, after the corrected consumption conversion information whose objective is its recording apparatus is obtained, its corrected consumption conversion information is used. For example, even in the case where an ink tank half-used is removed and then it is mounted on another recording apparatus, appropriate consumption conversion information is used.
The present invention can be realized in various aspects. The present invention is not limited to an ink consumption detection apparatus, may be an ink jet recording apparatus, may be a control apparatus of an ink jet recording apparatus, may be an ink tank, and may be the other aspects. In the case where the present invention is an aspect of an ink tank, preferably, an ink tank has a consumption information memory, and provides information necessary to the various kinds of processings described above, especially consumption conversion information. A typical ink tank is an ink cartridge attachable to/detachable from a recording apparatus.
One aspect of the present invention is a method of detecting an ink consuming state of an ink tank used for an ink jet recording apparatus. This method uses both of an estimate consumption calculation processing and an actual consumption detection processing in combination. In an estimate consumption calculation processing, an estimate consuming state is found by calculating an ink consuming state on the basis of an ink consumption of the ink tank. The ink consumption may be an ink consumption by printing, or may be an ink consumption for maintenance of an ink head and the like. On the other hand, an actual consumption detection processing detects an actual consuming state by detecting an oscillating state corresponding to an ink consuming state using a piezoelectric device. In the present invention, the actual consumption detection processing plurality of stages using a plurality of piezoelectric devices mounted on different locations of the ink tank.
In the present invention, although errors are somewhat accompanied with, a consuming state is found in detail by an estimate processing on the basis of an ink consumption. On the other hand, by employing a piezoelectric device, an actual consuming state can be precisely detected without using a complex sealing structure. Particularly, by employing a plurality of piezoelectric devices, an actual consuming state of a plurality of stages are found. An ink consuming state can be found precisely and in detail from the actual consuming state in a plurality of stages and the estimate consuming state.
Preferably, in the actual consumption detection processing, that an ink liquid level passes through the respective multiple piezoelectric devices is detected as the actual consuming state. In the estimate consumption calculation processing, a consuming state from the point in time when one piezoelectric device detects the passage of a liquid level portion to the point in time when the next piezoelectric device detects the passage of a liquid level portion is found as the estimate consuming state. Moreover, in the estimate consumption calculation processing, a consumption state after the lowest piezoelectric device detects the passage of a liquid level portion is found as the estimate consumption state. By these processings, when a liquid level portion passes through, a consumption state is precisely detected, and consumption states prior to and after the passage are complemented with estimations. As a result, the ink consumption state can be complemented continuously, precisely and in detail.
Preferably, in the estimate consumption calculation processing, when an ink liquid level passes through the respective multiple piezoelectric devices, consumption conversion information is corrected, the estimate consumption state is found on the basis of the corrected consumption conversion information. The foregoing consumption conversion information may be a volume of the ink corresponding to the number of ink droplets ejected from the recording head. The consumption conversion information may be information of a volume of an ink consumed when performing the maintenance. A consumption conversion parameter is different little by little due to ink jet recording apparatus and ink tanks, and further combinations thereof. Since the errors due to these differences of conversion parameters can be reduced, a consumption state can be more precisely found.
The corrected consumption conversion information may be used so as to be limited to an ink tank which is the objective of the correction. Or, the corrected consumption conversion information may be used for an ink tank subsequently mounted without limiting to the ink tank which is the objective of the correction. The latter is advantageous, for example, in the case where the influence to the consumption conversion parameter due to the individual differences of ink jet heads is large. The respective ink jet recording apparatus can utilize consumption conversion information applicable to their heads.
In the method of the present invention, when the lowest piezoelectric device detects the passage of a liquid level portion, until then the final consumption conversion information may be also found on the basis of the corrected results of consumption conversion information for a plurality of times accompanying with detections of the passages of liquid levels for a plurality of times. The foregoing estimate consumption state is found after the lowest piezoelectric device detects the passage of a liquid level portion by the respective multiple piezoelectric devices using this final consumption conversion information.
Preferably, the estimate consumption calculation processing is a processing for finding the estimate consumption state by adding up the number of ink droplets ejected from a recording head, when the passage of a liquid level portion is detected by the respective multiple piezoelectric devices, the estimate consumption state found by adding up until then is corrected. According to this form, when the actual consumption state is detected, the errors generated by estimate consumption calculation processing until then are corrected. Therefore, the ink consumption state can be precisely found.
The foregoing actual consumption detection processing section may detect an actual consumption state on the basis of a change of an acoustic impedance accompanied with a liquid consumption using the piezoelectric device. The foregoing piezoelectric device may output a signal indicating the remaining oscillating state after an oscillation is generated. The foregoing actual consumption state is detected on the basis of the remaining oscillation state being changed corresponding to an ink consumption state.
Moreover, a piezoelectric device may generate a detection signal corresponding to a reflected wave with respect to an elastic wave as well as generate the elastic wave toward the interior of the liquid container.
The foregoing ink tank which is the objective of detection of an ink consumption state is, typically, an ink cartridge attachable to/detachable from the ink jet recording apparatus. However, an ink tank is not limited to an ink cartridge, and applicable to a sub tank fixed on a recording apparatus and the like.
Another aspect of the present invention is an apparatus for detecting an ink consuming state of an ink tank used for an ink jet recording apparatus includes an estimate consumption calculation processing section for finding an estimate consumption state by calculating an ink consumption state on the basis of the ink tank, a plurality of piezoelectric devices mounted on different locations of the ink tank, and an actual consumption detection processing section for detecting an actual consumption state of the ink in a plurality of stages by detecting an oscillating state corresponding to an ink consumption state using the multiple piezoelectric devices.
One aspect of an ink jet recording apparatus according to the present invention can be attached to/detached from an ink tank having a piezoelectric device for housing the ink for supplying to a recording head for discharging an ink droplet and recording and detecting the ink. Moreover, the relevant ink jet recording apparatus comprises an estimate consumption calculation processing section for finding an estimate consumption state of the ink within an ink tank on the basis of the reference consumption conversion information related to a volume of the ink consumed from a head, an actual consumption detection processing section for detecting an actual consumption state by detecting an oscillating state corresponding to a consumption state of the ink within the ink tank using a piezoelectric device, a correction section for correcting the reference consumption conversion information on the basis of the determination that whether or not the reference consumption conversion information is made a correction objective is determined and making it an objective of the correction.
Preferably, the relevant ink jet recording apparatus finds an estimate consumption state by adding up the number of times of an ink consumption consumed from the recording head and a volume of the ink obtained from the reference consumption conversion information.
Preferably, the reference consumption conversion information are classified into at least different two unit information with each other. Moreover, the correction section determines at least any one of unit information out of two units information as a correction objective at least on the basis of the estimate consuming state. Moreover, the correction section may be previously set so as to determine at least one of unit information as a correction objective.
At least two unit information may be classified according to a volume of ink droplets discharged from the recording head. At least two unit information may be classified according to a printing state and non-printing state. At least two unit information may be classified according to a circumferential temperature recorded by the recording head. At least two unit information may be classified according to a temperature of circumference recorded by the recording head.
Preferably, the correction section corrects the reference consumption conversion information using a ratio between an estimate consumption state and an actual consumption state.
Preferably, the relevant ink jet recording apparatus has a storage section for storing the reference consumption conversion information. Preferably, the relevant ink jet recording apparatus has a storage section for storing the reference consumption information corrected by the correction section.
A factor of the reference consumption conversion information may be represented by a volume of ink droplets discharged from the recording head. A factor of the reference consumption conversion information may be represented by mass of ink droplets discharged from the recording head. A factor of the reference consumption conversion information may be represented by a ratio making an optional unit information as a reference. The estimate consumption calculation processing section may find an estimate consumption state on the basis of any of the reference consumption conversion information out of a plurality of the reference consumption conversion information.
One aspect of an ink tank according to the present invention is equipped with a container for housing the ink for supplying to a recording head discharging ink droplets, a liquid supplying opening for supplying the ink to the recording head, a piezoelectric device for detecting a consumption state of the ink within the container, and a storage section for storing the reference consumption conversion information classified into at least two kinds of unit information which are related to a volume of the ink consumed from the recording head and different from each other. The relevant ink tank can be attached/detached from an ink jet recording apparatus for recording by discharging ink droplets.
Preferably, the storage section stores the reference consumption conversion information classified into the corrected unit information on the basis of an estimate consumption state of the ink within the relevant ink tank on the basis of the reference consumption conversion information and an actual consumption state detected from an oscillating state corresponding to a consumption state of the ink within the relevant ink tank using a piezoelectric device.
The storage section may store the multiple reference consumption conversion information which are different from each other. Preferably, the number of the multiple reference consumption conversion information is determined according to the number of piezoelectric devices.
One aspect of the method of detecting an ink consumption according to the present invention is a method of detecting a consumption state of the ink of an ink tank which has a piezoelectric device for housing the ink for supplying to the recording head for discharging an ink droplet and detecting the ink and which is mounted so as to be attachable to/detachable from the ink jet recording apparatus, and has a detection step for finding an estimate consumption state on the basis of the reference consumption conversion information related to a volume of the ink consumed from the recording head and detecting an actual consumption state by detecting an oscillating state corresponding to a consumption state of the ink using a piezoelectric device, a correction determination step for determining whether or not the reference consumption conversion information is made a correction objective, and a correction step for correcting the reference consumption conversion information on the basis of the results of the determination that the correction in the correction determination step is performed.
In the correction determination step, the correction section may determine whether or not the reference consumption conversion information in the correction step is corrected by the relationship between an estimate consumption state prior to the detection step and the reference consumption conversion information in the detection step.
Preferably, the reference consumption conversion information are classified into at least two kinds of unit information different from each other related to a volume of ink droplets discharged from the recording head.
Preferably, the relevant method of detecting an ink consumption determines whether or not at least two kinds of unit information are made a correction objective on the basis of an estimate consumption state in the correction determination step.
In the correction determination step, when an estimate consumption state based on the second unit information is larger than an estimate consumption state based on unit information except for the first unit information with respect to a volume of an ink consumption or a rate of consumption, the second unit information may be made as a correction objective.
In the correction determination step, when an estimate consumption state based on the relevant unit information in the detection step is larger than any of estimate consumption states based on the relevant unit information prior to the detection step with respect to a volume of an ink consumption or a rate of consumption, the unit information may be determined as a correction objective.
In the correction determination step, unit information whose estimate consumption state is larger than a predetermined threshold with respect to a volume of an ink consumption or a rate of consumption may be determined as a correction objective.
In the estimate consumption calculation processing, an estimate consumption may be found by approximation using a linear calculation between factors of the reference consumption conversion information.
In the correction determination step, at least one of unit information out of unit information may be determined as a correction objective by a probable value of the error between an estimate consumption state and an actual consumption state.
Another aspect of the method of detecting an ink consumption according to the present invention has a first detection step for finding an estimate consumption state based on first reference consumption conversion information out of the multiple reference consumption conversion information related to a volume of the ink consumed from a recording head and detecting an oscillating state corresponding to a consumption state of the ink using a piezoelectric device, and a second detection step for finding an estimate consumption state based on second reference consumption conversion information which is different from the first reference consumption conversion information out of the multiple reference consumption conversion information and detecting an actual consumption state by detecting an oscillating state corresponding to a consumption state of the ink using a piezoelectric device.
The present aspect may have a modification determination step for determining whether or not the first reference consumption conversion information is changed to the second reference consumption conversion information which is different from the first reference consumption conversion information between the first detection step and the second detection step. In such a case, in the second detection step, according to the results of the modification determination step, an estimate consumption state is found based on the first reference consumption conversion information or the second reference consumption conversion information and an actual consumption state is detected by detecting an oscillating state corresponding to a consumption state of the ink using a piezoelectric device.
Preferably, in the estimate consumption calculation processing, an estimate consumption state is found by adding up the number of ink consumption consumed from the recording head and a volume of the ink obtained from the reference consumption conversion information.
Preferably, in the actual consumption detection processing section, an actual consumption state is detected based on a change of an acoustic impedance accompanied with an ink consumption using the piezoelectric device.
Preferably, in the actual consumption detection processing section, an ink consumption state is detected based on a counter electromotive force generated by the residual oscillation remained in the oscillating section that a piezoelectric device has.